The present invention is generally concerned with the construction of laminated sectional girders formed of fiber-reinforced materials and including webs and flanges which are formed to consist of a plurality of material layers. More specifically, the invention is directed to an arrangement wherein such girders may be formed to include at least one layer which is designed as both a web layer and as a flange layer thereby extending as a connecting layer through both a web and a flange of the girder.
In the construction of girders of fiber-reinforced materials of conventional design, the ability to withstand large sheer forces is difficult to accomplish because only the flange surface of the girder is generally available for sheer transmission.
In the prior art, a method for the production of supporting and flexural girders whereby the physical properties of girders of fiber-reinforced material may be improved, is known from German DOS No. 2, 334, 645. In this method, a wound hollow body of fibers impregnated with synthetic resin is divided into several parts, with the parts being subsequently assembled to different girder forms. The webs and flanges of such girders each consist of a plurality of layers so that the sheer transmitting surfaces may, from a practical point of view, be doubled. However, in girders of this type it occurs that the sheer forces which are to be transmitted are likewise far from sufficient to enable utilization of the full potential tensile strength of the fiber-reinforced material which is utilized.
The present invention is directed toward providing a structural arrangement for laminated section girders of fiber-reinforced materials whereby the girders may be adapted to transmit greater sheer forces.